Question on shipping a shotgun

[snake Dr]

I have a non c&r shotgun for sale that would need to be Dros'ed for sale. I have had a few offers which would require it to be shipped. If I am a Calif. resident selling to another Calif. resident can I ship it directly to his local FFL or do I have to have an FFL in my area ship it to his FFL? One of the potential buyers got rather nasty about the whole thing saying that I could ship it directly to his FFL. I asked my local FFL and he said if it is CA resident to CA resident then it must be shipped by an FFL to an FFL. So now I am not sure what the law is.

Can anyone clarify this for me.

Thanks

Mike